//===================================================================================
// Microsoft patterns & practices
// Composite Application Guidance for Windows Presentation Foundation and Silverlight
//===================================================================================
// Copyright (c) Microsoft Corporation.  All rights reserved.
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE.
//===================================================================================
// The example companies, organizations, products, domain names,
// e-mail addresses, logos, people, places, and events depicted
// herein are fictitious.  No association with any real company,
// organization, product, domain name, email address, logo, person,
// places, or events is intended or should be inferred.
//===================================================================================
using System.Linq;

namespace Microsoft.Practices.Prism.Regions
{
	/// <summary>
	/// Region that allows a maximum of one active view at a time.
	/// </summary>
	public class SingleActiveRegion : Region
	{
		/// <summary>
		/// Marks the specified view as active.
		/// </summary>
		/// <param name="view">The view to activate.</param>
		/// <remarks>If there is an active view before calling this method,
		/// that view will be deactivated automatically.</remarks>
		public override void Activate(object view)
		{
			object currentActiveView = ActiveViews.FirstOrDefault();

			if (currentActiveView != null && currentActiveView != view && this.Views.Contains(currentActiveView))
			{
				base.Deactivate(currentActiveView);
			}
			base.Activate(view);
		}
	}
}